施钾改善木薯农艺性状及淀粉组分

以2个木薯品种‘SC205’和‘SC124’为研究对象,设置不施钾（K₀,K₂O 0 kg/hm²）、低钾（K₅₀,K₂O 50 kg/hm²）、中钾（K₁₀₀,K₂O 100 kg/hm²）和高钾（K₂₀₀,K₂O 200 kg/hm²）4个施钾量处理,测定收获期木薯的农艺性状、鲜薯产量及其构成指标、可溶性糖组分含量、淀粉组分含量等指标。结果表明：（1）与不施钾相比,施钾量达100 kg/hm²以上时,能显著提高木薯株高、茎径、单条薯重;施钾量达50 kg/hm²以上时,能显著提高鲜薯产量,其中‘SC205’和‘SC124’的鲜薯产量增幅分别达59.2%~131.7%和51.4%~127.9%,在施钾量（K₂O）为100 kg/hm²时鲜薯产量达到最大值;（2）施钾量对不同组织可溶性糖组分含量及总淀粉含量、支链淀粉含量均有显著影响;品种与施钾量间交互作用对蔗糖含量具有显著影响,对其他可溶性糖组分及淀粉各组分均无显著影响（P>0.05）;（3）相关性分析表明,各组织的可溶性糖组分含量与块根淀粉组分含量间具有负的相关性,其中块根的可溶性糖组分与块根总淀粉含量具有显著或极显著的负相关,茎秆的葡萄糖和蔗糖含量与块根总淀粉含量具有显著负相关。综上所述,合理施钾促进了可溶性糖向淀粉的转化,进而有利于木薯鲜薯产量和品质的形成,对连作条件下木薯的提质增效具有重要的实践意义。

Potassium Application Improved the Agronomic Properties and Starch Components of Cassava

A field experiment was conducted to study the agronomic properties,tuber yield and components,soluble sugar and starch contents of two cassava varieties‘SC205’and‘SC124’with four K treatment:no potassium(K0,K2O 0 kg/hm^2),low potassium(K50,K2O 50 kg/hm^2),medium potassium(K100,K2O 100 kg/hm^2)and high potassium(K200,K2O 200 kg/hm^2).Compared to K0,K application amount greater than or equal to 100 kg/hm^2 would significantly improve the plant height,stem diameter and weight of single tuber for cassava,meanwhile,K application amount greater than or equal to 50 kg/hm^2 significantly improved the fresh tuber yield by 59.2%-131.7%and 51.4%-127.9%for‘SC205’and‘SC124’,respectively.When K application rate was 100 kg/hm^2,the fresh tuber yield reached the maximum level.Variance analysis showed that K rate had significant effects on the content of soluble sugar components,total starch and amylopectin in different organs.In addition,the interaction effect between variety and K rate was significant on the sucrose in different organ for cassava,while was no significant on others soluble sugar and starch components(P>0.05).The correlation analysis showed that there was negative relation between the content of soluble sugar components in different organs and content of starch components in tuber.There was significant or extremely negative relation between the content of soluble sugar in tuber and content of total starch,while there was significant negative relation between the content of stem glucose and sucrose and content of tuber total starch.In conclusion,reasonable K application improved the transformation of soluble sugar to starch,and which was benefit to the improvement of fresh yield and quality under continuous plantation for cassava.